The lowest triplet state of benzene: Differences in electronic structure in two crystalline modifications of a cyclohexane host

Microwave induced delayed phosphorescence (MIDP) measurements have been performed in the 00 bands of the phosphorescence spectrum of benzene dissolved in two phases of cyclohexane. From the relative radiative rates for decay of the three zero-field levels it is concluded that on the average the symmetry of the electronic structure is lower than D_2h. In the monoclinic low temperature stable phase of cyclohexane (phase II) the structure is approximately antiquinoidal, and in the metastable phase III it is approximately quinoidal.     

Dissociative ionization of methyl-substituted hydroxyquinolines

The mass spectra of the following methyl-substituted hydroxyquinolines have been studied in the range of energies of the ionizing electrons of 15–50 eV: 2-hydroxy-4-methylquinoline, 6-hydroxy-2-methylquinoline, 6-hydroxy-4-methylquinoline, 8-hydroxy-2-methylquinoline, 8-hydroxy-4-methylquinoline, 2,6-dihydroxy-4-methylquinoline, and 4,6-dihydroxy-2-methylquinoline. It has been shown that the processes of dissociative ionization for the series of compounds investigated take place exclusively from the keto forms of the molecular ions. The stability to electron impact is determined largely by the degree of enolization of the structures considered. The values of the selective decomposition are given and a scheme is proposed for the identification of the isomeric methyl-substituted hydroxyquinolines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 972–978, July, 1973.     

Über Blei (II)-oxidhydrat der Zusammensetzung 3PbO·H2O

Lead oxide hydrate mentioned in the earlier literature with several formulas between PbO · H₂O and PbO · 0.33 H₂O has been synthesized and investigated by high resolution X-ray powder methods, thermogravimetry and infrared spectroscopy. The unit cell was found from 62 powder reflections to be tetragonal with a = 8.009 ± 0.003 Å, c = 9.312 ± 0.005 Å, Z = 12 [PbO · 0.33 H₂O]. These data were confirmed by WEISSENBERG and Precession photographs of single crystals grown as a corrosion product on metallic lead. The space group is D–P4/mnc or C–P4 nc. Thermogravimetric measurements, corrected for a slight content of superficially bound carbon dioxide detected by infrared spectroscopy, lead to the most probable formula 3 PbO · H₂O or PbO · 0.33 H₂O. As infrared spectra show the presence of a HOH deformation vibration, the compound is considered to be an oxide hydrate and not an oxide hydroxide of lead.     

Reactions of diterpenoids on solid supports II. Behavior of di- and tricyclic diterpenoids on alumina containing oxidants

The behavior of epimanool (1), epimanool oil, larixol (2), cis-abienol (3) and methyl dehydroabietate (4) on alumina impregnated with oxidants (H₂CrO₄ and KMnO₄) has been studied. This has led to the methyl ketone (5) and norambrenolide (8) - precursors of the perfume substances 14,15,17-trinorlabdane-8,13-dione (6), 8-hydroxy-14,15-bisnorlabd-II-en-13-one (7), and methyl 7-oxodehydroabietate (14). -Levantenolide (11) has been synthesized in one stage from cis-abienol (3)for the first time.Novosibirsk Insitute of Organic Chemistry, Siberian Division of the Russian Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 229–234, March-April, 1995. Original article submitted July 25, 1994.     

Kinetics and Mechanism of Monomolecular Heterolysis of Commercial Organohalogen Compounds: XXVIII. Effect of the Nature of the Verdazyl Indicator on Salt Effects in Dehydrobromination of 3-Bromocyclohexene in Nitrobenzene

The salt effect on the rate of dehydrobromination of 3-bromocyclohexene in PhNO2 depends on the nature of the verdazyl indicator. With triphenylverdazyl and its chloro and nitro derivatives in the presence of Et₄NClO₄, a normal salt effect is observed, in the presence of bromides, a superposition of normal and special salt effects, while in the presence of chlorides, a superposition of normal and special negative salt effects. With the dimethoxy verdazyl derivative, a normal salt effect is always observed.     

Uranextraktion mit Triphenylarsinoxid

Analytical and Bioanalytical Chemistry - Es wird eine neue extraktive Trennungsmethode für Uran beschrieben. Mit Hilfe einer Lösung von Triphenylarsinoxid in Chloroform lassen sich...